If you hit the function button, then hit it again to lock the function keys, it doesn't lock the function key.
The delete key, hold shift and hit the back space button, it won't delete, meaning it won't remove the character to the right of the cursor. I saw this on the forum, and confirmed it on my pandora also.

SuperZaxxon Final 2012-07-03
Lock-Key: Now implemented, but some input still works.
Fn-U and FN-I (Screen brightness down/up): This is desirable.
Right-nub with default setting (left/middle/right/double click): This is a bug in my opinion.
Delete button (Shift-Backspace) still not working

Agreeing with you on the bug segregation.
Two different pair of shoes software-wise,
but hardware-wise it is ONE PHYSICAL BUTTON,
hence Tim Willey reported it at once, I guess.
Thanks for looking into the undesired nub lock exception.